This invention relates, in general, to directional filters/combiners and, more particularly, to dual adjacent directional filters/combiners.
Various types of directional filters are known in the art. See U.S. Pat. Nos. 2,922,123 entitled "Directional Filters for Strip-Line Transmission Systems" invented by S. B. Cohn; 3,447,102 entitled "Microwave Frequency Converting Comprising Multi-Port Directional Couplers" invented by J. W. Gewartowski; and 4,287,605 entitled "Directional Filter for Mixers, Converters and the Like" invented by Micheal Dydyk. While these devices can be modified to provide the signal splitting/combining provided by the dual adjacent directional filters, as will be seen below, excessive components are required which result in additional losses; require more space; and are more expensive.